Drilling bit



s p 1940 c. R. ATHY 1 D'RILLING BIT Filed Dec. 3, 19s? a sheets-sheet 1 ,Ul F i w I l H I 2 r ATTORNEY C. R. ATHY DRILLING BIT Sept. 24, 1940.

Filed Dec. 5, 1937 2 Sheets-Sheet 2 I ll INVENTOR C/z'ff ordR Athy BY Z ATTORNEY Patented Sept. 24, 1 940 DRILLING BIT Clifford R. Athy, Columbus, Ohio, assignor to The Pure Oil Company, Chicago, 111., a corporation of Ohio Application December 3, 1937, Serial No. 177,959

7 Claims.

This invention relates to method and means for locking and sealing separable devices and particularly to method and means for locking and sealing together multipaljt drilling bits used .in percussion well drilling operations.

Drilling bits commonly used in oil well drilling operations are made in one piece with the upper end or pin tapered and threaded to enable it to be screwed into the stem of the drilling string. I'rie blade of the bit becomes dull very rapidly when in. use, necessitating frequent removal from the hole, and dressing. The withdrawal ofthe tool from the hole and the removal of the bit from the stem is a time consuming and laborious operation.

Because of the fact that the blade becomes quickly dulled while in use, it is necessary to pro- 'vide a forge on the derrick floor of the drilling operation where the blade can be reheated and dressed in order to make it available for further use. Because the heat treatment at the derrick is rather crude and uncontrolled, it has been possible heretofore to use only plain carbon steel in the manufacture of bits. The use of high grade alloy steels has been prohibitive due to the fact.

that such steels require careful heat treatment.

Not only have drilling operations been limited by the fact that it has been necessary to use low grade steels and to remove the drilling bit frequently from the hole, but the great weight of the bit has made very difficult its removal, and replacement on the drilling stem.

One object of my inventionis to provide method and means for locking and sealing together parts which must'be frequently separated.

Another object of my invention is to provide a drilling bit of such nature that it will increase the speed of well drilling. Still another object of my invention is to provide a drillinghit which can be made out of hig grade alloy steel.

A further object of my invention is to provide a drilling bit made in.several parts so that only the blade need be removed for dressing.

thereof which requires dressing is made sufiiciently light and sufficiently cheap to enable the the forces and stresses to which it is subjected in operation without coming apart or breaking.

Other objects of my invention will be apparent from the following description considered in conjunction with the which,

Fig. 1 is a diagrammatic elevational view of a drilling bit made in accordance with my invention.

Fig. 2 is a cross-sectional view of the bit taken along the line 2-2 of Fig. 1

Fig. 3 is a diagrammatic elevational view of the shank end of the bit shown in Fig. 1.

. Fig. 4 is a plan view of the bottom of the shank 10 end shown in Fig. 3.

Fig. 5 be diagrammatic elevational view of the blade end of the bit shown in Fig. 1.

Fig. 6 is a plan view of the top of the blade end shown in Fig. 5.

Fig. 7 is a horizontal cross-sectional view similar to Fig. 2, showing a modified form of bit.

Fig. 8 is a'vertical fragmentary cross-section showing a modified form of pin structure.

Fig. 9 is a vertical-fragmentary cross-section 20 showing another modified form of pin structure.

Fig. 10 is a cross-sectional view of a modified form of pin.

Fig. 11 is a perspective view of tion of the pin. g5 Referringto the drawings, Figures 1 to 6, the numeral I indicates generally a drilling bit having a shank 3 and a blade 5. The lower end 6 of the shank is formed with a recess 1, counterbored at accompanying drawings, of

another modificae its lower end 9. The shoulder l l between the side 30 1 wall l3 of. the recess 1 and the sidewall l5 of the counterbore or socket 9 is tapered upwardly and inwardly for a reason to be subsequently described. The shank has a transverse bore ll extending 35 entirely therethrou'gh, a short distance above the upper end l9 of the recess 1. The bore I1 is slightly tapered from one end to the other and is adapted. to receive a plug 2|. which can be snugly driven into the bore. The plug is preferably pro- 40 vided' with" a circumferential groove 22$.intermediate the ends thereof. A narrow vertical passageway 23, located centrally of the shank, connects the bore IT with the recess 1. Pins 25 and 21 extend horizontally into the recess I intermediate the top and bottom of the recess. The pins 25 and 21 may be forged integrally with the shank or they may be welded, threaded or shrinkor hammer-fittedinto holes bored horizontally through the walls of theshank at diametrically opposite points. Although the pins are shown as being cylindrical, they may be any other suitable shape. Theupper end of the shank is formed with the threaded pin 29 which is adapted to be screwed into the stem of the drilling string.

The blade is formed with the cutting edges 3| alongthe bottom thereof and the serrations 32 along the sides thereof to engage fishing tools. The blade has a T-shaped extension 33 at the upper end thereof. The head 34 of the extension 60 is formed with the lugs 35 and 31 extending horizontally at diametrically opposite points. These lugs are shaped to be best adapted to interlock with the pins 25 and 21. The blade has a shoulder 39 between the extension 33 and the upper end 4| of the blade proper. The shoulder 39 is shaped to conform to the shape of the side walls l5 of the counterbore or socket 9, and is adapted to fit snugly therein to provide a seal against leakage of the sealing medium. The height of the shoulder should be such that when the upper face thereof abuts the lower face 6 of the shank, the lugs 35 and 31 will clear the pins 25 and 21 when the blade is rotated into locking posit-ion.

' e recess 1 may assume any desired shape but preferably conforms to the general shape shown in Figures 2 and 4. As shown, the recess assumes the form of two tangentialcircles joined together by two spaced lines perpendicular to the common tangent so that the width at the points of jointure is somewhat less than the diameter of the circles but sufficiently wide to accommodate the extension 33 of the blade.

As shown more clearly in Fig. '2, the recess is preferably of sufiicient width and length to just permit the head 34 of the extension 33 to pass beyond the pins 25 and 21. As shown, the head of the extension is relatively narrow compared to its length.

In assembling the bit, the extension 33 of-the blade end is inserted in the recess 1 with the T-head turned in the position shown in Fig. 2. The extension is then inserted far enough so that the lower sides of the lugs 35 and 31 are above the upper sides of the pins 25 and 21. The blade is then rotated until the lugs 35 and 31 are directly above the pins 25 and 21. As shown in Fig. 2, the pins 25 and 21 are so located that when the blade is rotated so that the lugs 35 and 31 are above the pins, the blade cannot be rotated any further since the lugs engage the side walls of the recess 1. The blade is then shimmed to its proper axial relationship with the shank, with the shoulder 39 fitted in the socket 9. The plug 2| is then removed and molten lead or other readily fusible metal or alloy, such as tin-lead alloys, is poured through the passageway 23 into the recess 1 until it is entirely filled. The plug 2| is then replaced and driven in place. When the lead or other metal or alloy solidifies, it fills the spaces between the extension 33 and the recess 1, preventing the blade from. turning. The

bit is then ready for operation.

In assembling the bit prior to pouring in the molten lead, the face or end 4| of the blade is not fitted tightly against the lower end or face 6 of the shank, thus providing slightly more space in the recess 1 than would be the case if the faces fitted snugly against each other. The shoulder fits in the socket sufiiciently close to prevent the molten metal from running out. During the drilling operation, the impact between the bottom of the hole and the bit tends to drive the blade into the recess of the shank therebycausing the solidified metal to pack more tightly in the recess and to make afirmer joint. The metal also packs into the groove 22 of the plug l1 thereby preventing the plug from being jarred loose.

The solidified metal is maintained in the 'recess by the fit made between the shoulder 39 and the socket 9. The tapered shoulder l I 'permits any solidified lead in the counterbored portion of the shank to be forced upwardly into the main portion of the recess and to be packed more tightly therein.

By providing a joint of this kind, the solidified metal prevents rotation of the blade in the shank to the unlocked position and the pins 25 and 21 prevent the blade from slipping out of the shank due to vertical or pulling stresses during the lifting or jarring-up of the bit.

When the blade becomes dull and requires replacement, it is merely necessary to remove it from the hole and heat the joint between the blade and the shank in order to melt the metal, remove the tapered pin or plug 2 I, and rotate the blade to the unlocked position whereupon it can easily be removed. Since the blade is relatively light in comparison to the total weight of the bit, it caneasily be handled and shipped back to the factory where it can be properly heat treated and dressed.

In the modification shown in Fig. 7, the pins 25 and 21 are removable and the recess 1 conforms in shape to the shape of the head 34' of the extension. The extension 33' is adapted; to be slipped straight into the recess 1' and fit fairly snugly therein. After the blade and shank ends are assembled, the pins 25' and 21 are placed in holes bored through the side walls of the shank end, and the bit sealed together with readily fusible metal or alloy as heretofore described.

Since, in this modification it is not possible to rotate the blade in order to remove it from the shank, it is necessary to have removable pins. The pins may be held in place in any suitable manner. As shown in Fig. 8, this is done by providing an annular groove 43 in the holes in which the pins 25' and 21' fit and providing the pins with circumferential grooves 45 and longitudinal grooves 41 extending from the circumferential groove to the inner end of the pin. The circumferential groove on the pin is located so that when the pin is tightly driven in the hole in the side wall of the shank, the groove is in line with the annular groove of the hole. When the sealing lead or alloy is poured into the recess 1, some of it will find it way through groove 41 into the grooves 43 and 45, where it will solidify and seal the pin in the hole.

The pins 25' and 21' are provided with heads 49 of smaller diameter than the main body of the pin, and are recessed at 5| where the head joins the main body of the pin in order to enable a tool to be applied to the pin to remove it from the hole when it is desired to change the blade.

As shown in Figures 9 and 11, the pin 25" and 21" are threaded into the hole. In this modification of the pin, the pin and hole are threaded and pr vided with grooves similar to those described n connection with Fig. 8. The head 53 of the pin is provided with a diametric recess 55 in order to enable the pin to be screwed in and out of the hole.

Although I have shown pins of frustro-conical shape, other shapes may be used and other means for holding them in place may be used.

By providing a separate blade, the blade can be made ofhigh grade alloy steels which will maintain their cutting edge for considerably longer periods than ordinary carbon steel. These blades can be made relatively cheap and light thereby enabling the producer to keep on, hand a large supply so that the blades can be dressed at the factory instead of at the derrick floor. Furthermore, by providing a separate blade portion, it is possible to build a stern and shank portion in one piece thereby eliminating the necessity of providing a separate shank which must be screwed into the stem. In such case the lower end of the stem would be formed in the manner described in connection with the shank. In the accompanying claims, the term shank or shank end refers to structure in which the stem and shank are made in separate pieces or inone piece.

In my preferred construction, the blade fits loosely with the recess of the shank in order to allow space for the sealing metal or alloy to flow into and solidify. The solidified sealing material acts as a cushion and thereby prevents direct contact between the metal of the shank and blade end and reduces the amount of wear between the parts. My invention is not limited to the loose construction but is intended to cover any construction, whether the parts are loosely or snugly fitted together, in which the locking elements are sealed by means of a fusible metal or alloy.

It will be apparent that the passageway for pouring molten metal into the assembled bit may be located in the blade instead of the shank, but I prefer to have the passageway in the shank.

The specific bits shown and described are for purposes of illustration only and it is to be understood that-the invention is not limited to these {specific forms. The invention is intended: to broadly cover all constructions in which parts are intended to be joined together in interlocking arrangement with the joint sealed with a fusible material, and particularly to drilling bits in which the blade is formed as a separate part of the bit and adapted to be interlocked with a shank and the interlocking parts sealed'with fusible metal.

What is claimed is:

1. A drilling bit comprising a shank and a separate blade, an axial recess in the lower end of said shank, projections extending from the side walls of said shank into said recess, an extension on the upper end of said blade, said extension having horizontally projecting lugs adjacent the upper end thereof, said extension being adapted to be inserted in said recess and rotated therein so that said lugs interlock with said projections, the unoccupied space in said recess being filled with a readily fusible metal or alloy forming the only positive means of securing said projections and lugs in interlocking engagement and a passageway from the exterior of the shank tosaid recess and a closure for said passageway.

2. A rilling bit comprising a shank and a separate blade, a long and narrow axial recess in the bottom of said shank, a pair of pins extending horizontally from diametrically opposite points of the walls of the shank into the recess, intermediate the top and bottom thereof, a long, narrow axial extension formed on the top of said blade, said extension having a pair of oppositely projecting lugs adjacent the top thereof, said recess being counterbored at the lower end to provide a socket to accommodate a shoulder formed on the lower end of said extension, the recess also being adapted to accommodate the extension and permit partial rotation of the extension in the recess so that the lugs are'brought into interlocking relationship with said pins, the unoccupied space in said recess being filled with a readily fusible metal or alloy forming the only positive means of securing said pins and lugs in interlocking relationship, a passageway from the exterior the extension on of the shank to said recess, and a closure for said passageway.

3; A drilling bit compri 'ng separate shank and blade ends, an axial recess in the lower end of said shank end, an axial extension on the upper end of said blade end, horizontally projecting lugs on said' extension, said extension being adaptedto fit upwardly into said recess, removable pins adapted to project horizontally through holes in the walls of the shank end into said recess, and to support said lugs from directly below when the bit is assembled, the unoccupied space in said recessbeing filled with a readily fusible metal or alloy .forming the only positive means of securing said lugs and pins in interlocking rela tionship and a passageway from the exterioroi the shank to said recess and a closure for said passageway.

4. A drilling bit in accordance with claim 3 in which the pins are provided with means to enable them to be sealed in the holes of the shank end by means of a readily fusible metal or alloy.

5. A drilling bit comprising separate shank and blade ends, an axial recess in the lower end of said shank end; an axial extension on the upper end ofsaid blade end, horizontally projecting lugs on said extension, said extension being adapted to fit upwardly into said recess, said recess be, ing counterbored at the lower end to provide a to support said lugs from directly below when" the bit is assembled, the unoccupied space in said recess being filled with a readily fusible metal or alloy forming the only positive means of securing said lugs and pins in interlocking relationship.

6. A drilling bit comprising separable shank and blade elements said elements having an extension on one element and a recess on the other, said recess being adapted to receive said extension and being counterbored at the lower end to provide a socket to accommodate a shoulder formed on the lower end of said extension, each element being provided with means to interlock with the other when the elements are assembled and the unoccupied space in said recess filled with areadily fusible metal or alloy forming the only positive means of securing the interlocking means in interlocking relationship. r

7. A drilling bit comprising a shank and a separate blade, an axial recess in the lower end of said shank, projections extending from the side walls of said shank into said recess, anextension on the upper end of said blade having projecting lugs adjacent the upper end thereof, said recess being counterbored at the lower end to provide a socket to accommodate a shoulder formed on the lower end of said extension, the recess also being adapted to accommodate the extension and permit rotation of the extension so that the lugs interlock with the projections, the unoccupied space in said recess being filled with a readily fusible metal or alloy forming the only positive means of securing said lugs and projections in interlocking relationship and a passageway from the exterior of the shank to said recess and a closure for said passageway.

CLIFFORD R. A'IHY. 

